Is Intravenous Immunoglobulin Effective in Reducing the Risk of Mortality and Morbidity in Neuroinvasive West Nile Virus Infection? A Critically Appraised Topic

Background: The clinical benefit of intravenous immunoglobulin (IVIG) in adult individuals with neuroinvasive West Nile virus (niWNV) infection is not well substantiated. We sought to critically assess current evidence regarding the efficacy of IVIG in treating patients with niWNV. Methods: The objective was addressed through the development of a critically appraised topic that included a clinical scenario, structured question, literature search strategy, critical appraisal, assessment of results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and a content expert in the field of neuro-infectious diseases. Results: The appraised study enrolled 62 participants with suspected niWNV, randomized into 3 different arms [37 participants in the Omr-IgG-am group, 12 in the Polygam group, and 13 in the normal saline (NS) group]. Omr-IgG-am and Polygam are different formulations of IVIG. IVIG safety, measured as rates of serious adverse events, was the primary study outcome while IVIG efficacy, measured as rates of unfavorable outcomes, was a secondary endpoint. The estimated rates of SAE were statistically similar in all groups (51.4% Omr-IgG-am, 58.3% Polygam, and 23.1% NS groups). Unfavorable outcomes also occurred at a similar rate between all the groups (51.5% Omr-IgG-am, 54.5% Polygam, and 27.3% NS). Conclusions: The appraised trial showed that Omr-IgG-am and Polygam are as safe as NS. Data on efficacy from this trial were limited by a small sample size. Phase III clinical trials on IVIG efficacy in NiWNV infection are needed.